For example in the case of what are known as capless fuel filler devices (capless fuel filler systems), for example two closing flaps are pivotably mounted in a filler pipe, one behind the other as viewed in an insertion direction of a fuel filler nozzle. As a rule, the closing flaps are in each case biased by a spring element into a closed position in which they close a passage through the filler pipe for fuel, for example. When the fuel filler nozzle is inserted, it butts by way of its free end firstly against the first closing flap and pivots the latter counter to the spring bias into an open position in which it allows the passage of the fuel filler nozzle. Subsequently, the fuel filler nozzle butts against the second closing flap and pushes the latter, too, counter to the spring bias into an open position in which this second closing flap also allows the passage of the fuel filler nozzle. The vehicle tank can subsequently be filled with fuel via the fuel filler nozzle. After the tank filling process is complete, the fuel filler nozzle is pulled out of the filler pipe again, wherein said fuel filler nozzle initially passes out of the passage opening opened by the second closing flap. The second closing flap thereupon moves back into the closed position on account of its spring bias. Subsequently, the fuel filler nozzle is also pulled out of the passage opened by the first closing flap, and the first closing flap, too, moves back into its closed position on account of its spring bias. Fuel filler devices of this type are also known, which have only one pivotably mounted closing flap in the filler pipe.
As a rule, it is necessary to allow the fuel filler device to be aerated or ventilated, in particular on the vehicle-tank side. Thus, pressure differences between the tank-side interior of the fuel filler device and the exterior, facing the outer environment, of the fuel filler device have to be ensured. To this end, corresponding valves are required which, in the prior art, are integrated into the one or more closing flaps. In particular in the case of capless fuel filler devices, in which thus no outer cap that closes the filler pipe is provided, the closing flaps provide a seal in their closing position with respect to the passage of liquid and gas. The provision of valves for aeration and ventilation is indispensable in such a case.
On account of the valves to be integrated, the closing flaps of the prior art have a complicated structure. Furthermore, in particular when a plurality of closing flaps are provided, it is necessary, in a complicated manner, to equip each of the closure flaps with a corresponding valve. These are then arranged in series and have to be coordinated with one another in a complicated manner for suitable aeration and ventilation.
Proceeding from the explained prior art, the invention is based on the object of providing a fuel filler device of the type mentioned at the beginning, which allows reliable aeration and ventilation in a structurally simple and robust manner.